The Morphology Unit and Imaging Core will provide for analyses of atherosclerosis in animal models, providing measures of extent, rate of progression and composition using both conventional and novel techniques. For this PPG renewal, the Morphology Core will be consolidated in one location, at UCSD under direction of Dr. Yury Miller. The overall goal will be to provide Investigators in the Projects both conventional and novel techniques to assess atherosclerosis. The 1st Specific Aim is to provide quantitative measurements of the extent of atherosclerosis in animal models. This includes conventional analysis of en face lesions, lesion volume at the root ofthe aorta, and recently, lesion volume in the abdominal aorta. The 2nd Specific Aim is to provide quantitation of macrophage infiltration in atherosclerotic lesions by use of laser scanning confocal microscopy and immunofluorescent techniques, including those previously developed by Dr. Curtiss. The 3rd Specific Aim will provide qualitative and quantitative imaging analysis of tissue and cellular morphology. This includes the provision of non-fixed tissues for gene expression studies, paraffin embedded or frozen sections for lesion or cellular morphology, and also includes laser capture microdissection as needed. Specific Aim 4 will provide dissected peri-aortic adipose tissue from the thoracic and abdominal aortas. This is a new function that will meet the new focus on peri-aortic adipose tissue that will be a major area of study for Project 2, and to a lesser extent in Project 3. The Morphology and Imaging Core is widely used by Investigators ofthe PPG and has evolved to meet new needs as noted. We anticipate that it will continue to provide a centrally important role in the life ofthe PPG.